Biodegradable waste is the type of waste that can be broken down by way of composting (aerobic decomposition and anaerobic decomposition) into base compounds (H2O, CO2, compounds of Nitrogen, Phosphorus, Potassium and others), energy (heat) and residual humus. The residual humus can eventually break down into fine particles and can be automatically transported by water circulation.
Biodegradable wastes are produced in huge volume from human activities. They include solid wastes such as kitchen food wastes and backyard plant wastes as well as packaging wastes (papers, cartons and wood pallets etc.), waste waters such as from sinks of kitchen and from sinks, showers, bathtubs as well as toilets of bathroom, and exhaust gases such as from furnace vent and stove vent. Households and industries in agriculture, restaurant and food production, etc. are all producers of the wastes.
It is a labour burden task to collect the wastes from households and industries and to transport them into municipal treatment centers. Producers of the wastes also need to spend time and labor to get them ready to be collected. Greenhouse gas emission from transportation of the wastes and the recycled result products such as compost is one of the inputs leading to climate change. It costs a lot of money from both private and public in building and maintaining the urban sewage piping systems for transporting the waste waters into municipal treatment centers. Exhaust gases discharged directly into atmosphere without treatment from households and industries increase air pollutions.
Recycling the above wastes in the municipal treatment centers by way of composting, incineration or landfill etc. can recover some part of the beneficial ingredients from the wastes treated, but also pollutes the atmosphere, soil and even groundwater. Furthermore, it also needs large lands and costs a lot in building and maintaining the treatment utilities.
A lot of efforts have been made in addressing treatment of the biodegradable wastes within the source location. Composters including vermi-composters that use natural ventilation are not in a sealed vessel therefore let go heat, odors and exhaust gases into the atmosphere.
The patent number U.S. Pat. No. 5,744,351 to Michael Bryan-Brown discloses a bioreactor for aerobically composting organic waste inside a sealed container. It integrates a mixing assembly and an aeration system so that the composting wastes can be ventilated inside the container. However, this design type needs to manage the exhaust gases by way of a bio-filter and to manage the leachate liquid by use of a pump.
The patent application No. CN101823069 by Aimin Li et al discloses an auto-controlled composter with ventilation and heat components to promote the composting processes inside the vessel. Again it still needs components to filter the exhaust gases and to manage the leachate liquid.
Both the above composters are designed for the purpose to recycle the bio wastes into compost only. The bio wastes are fed by batch into the composter, after certain time the completed compost is to be discharged and transported. Pollutants to environment can be disposed from the exhaust gases, the leachate liquid and the completed compost. Nutrients of the bio wastes and heat from the composting wastes are not fully utilized. When these composters are employed, the bio wastes inside the vessel of a batch undergo all the composting stages, therefore the quantity of microorganisms of each stage reaches its highest point at its stage and then decreases or even disappears in other stages because of changed conditions. When the complete compost of the batch is discharged, the microorganisms inside the composter are also discharged. It is a total new process for microorganisms to grow into large quantities during the new composting stages of the newly fed batch of bio wastes.
It is desirable that the biodegradable wastes be composted within its source location with the completed compost locally used with zero mile of transportation, with zero pollution to the environment from the composting processes, and with all the nutrients and heat energy from the wastes fully recovered and reused. It is also desirable that the condition of microorganisms stay unchanged when the biodegradable wastes undergo each of the composting stages.
In response to the growth of demand for healthy foods available in minimum mileage, the hydroponics system and the aquaponics system have been in practice for decades. When these practices happen in the household backyard or in the food consume premises, zero food mileage can be achieved as regard to the foods produced and consumed in the same location.
However, the conventional hydroponics system needs to add artificial nutrients into the circulating water to feed the plants. In the typical aquaponics system, fish feed is from outside source, and the waste water from integrated fishing tanks doesn't have enough nutrients to support the growing plants, therefore minerals and other nutrients have to be added. Furthermore, a filter and a bioreactor are required to separate and to degrade the solid wastes in the waste water from the aquaponics fish tanks.
However, one can use, for instance, compost tea to supply nutrients. Compost tea is produced by putting a bag of compost into a vessel with aerated water for certain time to allow microbes grow. It is nutritious for feeding plants and therefore good to be added into the hydroponics and aquaponics systems. Different devices are available but are separately operated.
Although it is valuable to grow short mileage foods with little water loss by way of the hydroponics system or the aquaponics system, their values are limited by the high start-up costs comparing to the volume of foods produced, for they are used to grow foods only. The systems do not have the function to automatically recycle the waste biomass produced from the systems and other sources.
It is desirable to have a bioreactor system that can be integrated into the hydroponics system or the aquaponics system, which can onsite automatically recycle biodegradable wastes into nutrient liquid to feed the growing plants, and that can also grow feed for the aquarium animals. Furthermore, it is desirable to have a bioreactor system that can be integrated into the food growing systems, that can automatically recycle all the biodegradable wastes including solid wastes, waste waters and exhaust gases from both the food production sources and from the onsite human activities, and that can fully recover nutrients and heat energy from the treated wastes to produce foods with zero pollution to the environment.
The patent application No. CA2759981A1 by Nicholas Hermes and James Sawada discloses a food production system that composts biomass and uses the completed compost to grow foods with heat and nutrients recovery. In this system biomasses are fed by batch mode to a composter and then physically transferred into another invertebrate culture unit and lastly transferred into a food culture unit. The heat recovery is carried by way of a complicated pipe system which circulates heat exchange liquid. In this design, the biomass is not kept inside of a sealed vessel during all processes; pollutants to environment can be disposed from the exhaust gases while nutrients and heat are not fully recovered.
In the prior art composters that can be employed onsite of the waste source, the biomasses or the bio wastes or the organic wastes or the biodegradable wastes that can be fed into the composter, have numerous limitations. The wastes such as wood pallets, tree trunks and branches of large size are usually not acceptable. The present invention provides an onsite biomass composting and reuse, which overcomes all the limitations of the prior art.
One of the important steps for sealed in-vessel composting is to mix or agitate the inside contents so that all the volume is well aerated. Either a slow speed motor that rotates the whole vessel/drum or a high speed motor that drives an agitator to cause movements of the whole volume is usually employed. In the U.S. Pat. No. 5,744,351, a vertically installed slidable mixing assembly is employed so that almost all the inside volume can be reached for agitation. This method requires a worker to manually operate the mixing assembly. In the patent application CN101823069, a mixing module is horizontally installed and it horizontally rotates the whole volume inside the vessel. All these methods are not efficient in comparing the power energy required with the simple aeration resulted.
The traditional plow is typically much more efficient in comparing the power required with the volume of mass (soil) moved. Inside a sealed vessel, if some part of the contents along the bottom layer is physically moved, it can cause somewhat movements of the whole contents. This kind of movements are good enough for aeration of the whole volume, especially if the air is from a space below the volume. Desirably a very slow speed of movements caused by rotating a plow type agitator inside the lower layer of the volume can well aerate the whole volume.
Also, most prior art agitators for in-vessel liquid agitation are designed for high speed rotation movements that cause movements of the whole volume. During very slow rotation, the volume and the dimensional range moved by these agitators are very limited therefore can not reach good agitation effects. It is desirable to have a specially designed liquid agitator that can reach better agitation effects from slow speed rotation, especially for the concaved or conical volume in which the height gradually decreases from the middle point to the side wall point.
One of the methods to heat greenhouse is to use a rocket stove by burying the chimney tube in ground to hold heat from the circulating combustion smoke underground. This is a right way to “degrade” by burning large branches and tree trunks which cannot be acceptable to the onsite composter. But this method causes exhaust gas emission because the combustion smoke goes directly into the atmosphere.
Studies have been applied in treatment of wastewater by using the Microbial Fuel Cell (MFC) technology. MFCs consume by microorganism organic matter of the waste water to produce electricity and therefore speed the treating processes of waste water. Temperature is one of the factors that affect the efficiency for MFCs to produce electricity.
In recycling the bio-degradable wastes into good staff for growing uses, the prior arts tend to deal the processes separately therefore don't solve the problem in high efficiency and even cause problems to each other. The apparatuses designed to treat solid wastes take the leachate liquid and exhaust gases as extra burdens which have to be specially managed. The apparatuses designed to treat waste waters take the solids inside as extra burdens which have to be specially managed. The apparatuses designed to treat exhaust gases have to employ liquid and solid filter media. The apparatuses designed to produce compost tea have to create conditions to grow microorganisms from the completed compost in which most of the microorganisms are not in the best state of activity and quantity. The apparatuses designed for vermi-composting have to manage the humidity of the fed solid waste, and the fed waste has to undergo a first stage of composting before it becomes food for worms. In winter we need to buy fire woods or gas to heat a green house while we put a lot of staff that is good for heating by burning into garbage bins that causes a lot afterward works to have it treated somewhere far away.
In the patent application US 2007/0059819A1, Stephen Storch discloses an apparatus for brewing compost tea which is composed of a plurality airlift pumps for agitation and aeration. This design causes a vortex swirl circulation in the tank. Most of the nowadays apparatuses used for brewing compost tea have employed this technique, however, in all the apparatuses the vortex swirling is created for agitation and aeration only, the kinetic energy of the vortex swirling is not harnessed for use.
It is desirable to have an integrated system that has functions of all the above mentioned prior art apparatuses and that can make every burden into good use. It is further desirable that the kinetic energy from the vortex swirling can be harnessed for uses in an integrated system such as mixing and agitating the solid wastes. It is also desirable to have a specially designed turbine that can harness the kinetic energy from the vortex swirling in high efficiency.